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Abstract:

A solar cell module includes: two solar cells, each including: a first
main face and a second main face; a first electrode on the first main
face, comprising a bus-bar electrode having at least one of an opening
portion, notch portion, and gap portion; and a second electrode on the
first or second main face having a polarity opposite to that of the first
electrode; a wiring member that electrically connects the first electrode
of one solar cell to the second electrode of another solar cell; and an
electrically conductive connection layer that contacts the wiring member
and the first main face.

Claims:

1-5. (canceled)

6. A solar cell module, comprising: two solar cells, each including: a
first main face and a second main face; a first electrode on the first
main face, comprising a bus-bar electrode having at least one of an
opening portion, notch portion, and gap portion; and a second electrode
on the first or second main face having a polarity opposite to that of
the first electrode; a wiring member that electrically connects the first
electrode of one solar cell to the second electrode of another solar
cell; and an electrically conductive connection layer that contacts the
wiring member and the first main face.

7. The solar cell module according to claim 6, wherein: the first
electrode comprises a plurality of finger electrodes with a constant
spacing between adjacent finger electrodes, and wherein the opening
portion length in the longitudinal direction of the wiring member is
smaller than the constant spacing between adjacent finger electrodes.

8. The solar cell module according to claim 6, wherein: the opening
portion length in the longitudinal direction of the wiring member is
smaller than the width of the bus-bar electrode.

9. The solar cell module according to claim 6, wherein: the conductive
connection layer contacts the first main face at the bottom of the at
least one of an opening portion, notch portion, and gap portion.

10. The solar cell module according to claim 6, wherein: the conductive
connection layer contacts the wiring member and the first main face
through the at least one of an opening portion, notch portion, and gap
portion.

11. The solar cell module according to claim 6, wherein: the conductive
connection layer is thicker than the bus-bar electrode.

12. The solar cell module according to claim 6, wherein: the conductive
connection layer is thicker than the depth of the at least one of an
opening portion, notch portion, and gap portion.

13. The solar cell module according to claim 6, wherein: the opening
portion width in the orthogonal direction of the wiring member is smaller
than the width of the wiring member.

14. The solar cell module claim according to claim 6, wherein: the
bus-bar electrode area of the first face that contacts the first main
face is larger than the bus-bar electrode area of the second face.

15. The solar cell module claim according to claim 6, wherein: each of
the at least one of an opening portion, notch portion, and gap portion is
positioned at equal intervals in a direction parallel with the longer
side of the bus-bar electrode.

16. The solar cell module claim according to claim 6, wherein: the first
electrode comprises finger electrodes, the bus-bar electrode has opening
portions, wherein each opening portion includes a first opening
sub-portion, and a second opening sub-portion adjacent to the first
opening sub-portion, the first opening sub-portion is positioned at a
first area between adjacent finger electrodes, and the second opening
sub-portion is positioned at a second area adjacent to the first area.

17. The solar cell module according to claim 6, wherein: the first
electrode comprises a first finger electrode, a second finger electrode,
and a third finger electrode adjacent to the first finger electrode and
the second electrode, the bus-bar electrode comprises opening portions,
wherein each opening portion includes a first opening sub-portion and a
second opening sub-portion adjacent to the first opening sub-portion, the
first opening sub-portion is positioned at a first area between the first
finger electrode and the third finger electrode, and the second opening
sub-portion is positioned at a second area between the second finger
electrode and the third finger electrode.

18. The solar cell module according to claim 6, wherein: the first
electrode comprises finger electrodes, and the bus-bar electrode has
opening portions, wherein each opening portion is positioned between
adjacent finger electrodes.

19. The solar cell module according to claim 6, wherein: the opening
portion is square as seen from a plan view.

20. A solar cell module, comprising: a solar cell, comprising: finger
electrodes; and a bus-bar electrode, comprising opening portions that
include a first opening sub-portion positioned at a first area between
adjacent finger electrodes; and a second opening sub-portion adjacent to
the first opening sub-portion and positioned at a second area adjacent to
the first area; a wiring member that electrically connects the bus-bar
electrode; and a electrically conductive connection layer between the
bus-bar electrode and the wiring member.

21. The solar cell module according to claim 20, wherein: each of the
opening portions is positioned at equal intervals in the direction
parallel with the longer side of the bus-bar electrode.

22. The solar cell module according to claim 20, wherein: each opening
portion is positioned between adjacent finger electrodes.

23. The solar cell module according to claim 20, wherein: the opening
portion width in the orthogonal direction of the wiring member is smaller
than the width of the wiring member.

25. A solar cell module, comprising: a solar cell, comprising: finger
electrodes; and a bus-bar electrode having a opening portion, wherein the
opening portion length in the longitudinal direction of the wiring member
is smaller than the spacing between adjacent finger electrodes; a wiring
member that electrically connects the bus-bar electrode; and a
electrically conductive connection layer between the bus-bar electrode
and the wiring member.

Description:

CROSS REFERENCE TO RELATED APPLICATION

[0001] This application is based upon and claims the benefit of priority
from the prior Japanese Patent Application No. P 2006-322084, filed on
Nov. 29, 2006; the entire contents of which are incorporated herein by
reference.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to a solar cell module in which the
connecting electrodes of solar cells are electrically interconnected by
wiring members.

[0004] 2. Description of the Related Art

[0005] The solar cell attracts attention as a new environmentally friendly
energy source, because it can convert light from the sun, which is an
unlimited source of clean energy, directly into electricity.

[0006] When such the solar cell is used as a power source (energy source),
since a single solar cell produces an output of approximately a few watts
at most, the solar cell is generally used not in units of one solar cell
but in the form of a solar cell module. In the solar cell module, as will
be described below, a plurality of solar cells are connected in series to
increase an output to 100 watts or greater.

[0007] Conventionally, in the solar cell module, the connecting electrodes
of a plurality of solar cells are electrically interconnected by wiring
members made from a conductive material such as copper foil. The solar
cells are sealed with a translucent sealing member made of EVA (Ethylene
Vinyl Acetate) or the like, between a acceptance face protective member
made of glass, translucent plastic, or the like and a back face
protective member made from a film of PET (PolyEthylene Terephthalate) or
the like.

[0008] In the solar cell, a pair of electrodes for output extraction is
formed on main faces of a photoelectric conversion body. In general, the
pair of electrodes is formed on the acceptance face and back face of the
photoelectric conversion body, respectively. In this case, the electrode
provided on the acceptance face is formed into a comb-like shape having a
plurality of finger electrodes and a bus-bar electrode formed of a
conductive paste. The wiring member is bonded by a solder onto the
bus-bar electrode provided on the acceptance face of one solar cell and
onto the bus-bar electrode provided on the back face of another solar
cell, whereby a plurality of solar cells are connected in series (for
example, see Japanese Patent No. 3754208). Accordingly, the bus-bar
electrode, the solder, and the wiring member are stacked in layers in
this order at least on the acceptance face of the photoelectric
conversion body.

BRIEF SUMMARY OF THE INVENTION

[0009] The present invention has been made to solve the above-mentioned
problems, and an object thereof is to provide a solar cell module that is
highly reliable against the temperature changes.

[0010] A first aspect of the present invention is the provision of a solar
cell module, comprising: two solar cells, each including: a photoelectric
conversion body which has first and second main faces and generates
photogenerated carriers; a first electrode which is provided on the first
main face, has a plurality of finger electrodes for collecting the
photogenerated carriers generated in the photoelectric conversion body,
and has a bus-bar electrode for collecting the photogenerated carriers
collected by the plurality of finger electrodes; and a second electrode
which is provided on any one of the first and second main faces and has a
polarity opposite to that of the first electrode; and a wiring member for
electrically connecting the first electrode of one solar cell of the two
solar cells to the second electrode of the other solar cell, wherein: the
wiring member is connected onto the bus-bar electrode of the first
electrode of the one solar cell through a connection layer formed of a
first conductive resin containing conductive material.

[0011] A second aspect of the present invention is related to the first
aspect of the present invention, and is summarized in that the connection
layer is in contact with the first main face of the photoelectric
conversion body in a region where the connection layer overlaps with the
wiring member when viewed in a direction perpendicular to the first main
face.

[0012] A third aspect of the present invention is related to the second
aspect of the present invention, and is summarized in that the bus-bar
electrode has any one of at least one of opening portion, notch portion,
and gap portion, and the opening portion, notch portion, or gap portion
is filled with the connection layer, whereby the connection layer is in
contact with an exposed portion of the first main face of the
photoelectric conversion body.

[0013] A fourth aspect of the present invention is related to the first
aspect of the present invention, and is summarized in that the bus-bar
electrode is formed of a second conductive resin containing conductive
material, and adhesive strength of the first conductive resin to the
first main face is stronger than adhesive strength of the second
conductive resin to the first main face.

[0014] A fifth aspect of the present invention is related to the first
aspect of the present invention, and is summarized in that, in the
bus-bar electrode, an area of a first face which comes in contact with
the first main face is larger than an area of a second face which is a
reverse of the first face.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0015]FIG. 1 is a section view showing an overall configuration of a
solar cell module according to an embodiment of the present invention.

[0016] FIG. 2A is an enlarged section view of solar cells 1a and 1b and a
wiring member 2a shown in FIG. 1.

[0017]FIG. 2B is a plane view of the solar cells 1a and 1b and the wiring
member 2a.

[0018]FIG. 3 is an enlarged section view of the vicinity of an acceptance
face of the solar cell 1a, taken along the line in FIG. 2B.

[0019]FIG. 4 is a section view to describe the electrical connection
between a bus-bar electrode 11a and the wiring member 2a shown in FIG. 3.

[0020]FIG. 5 is a plane view showing the solar cell 1a before the wiring
member 2a is connected.

[0021] FIG. 6 is a plane view showing the solar cell 1a before the wiring
member 2a is connected, according to a first modification example.

[0022] FIG. 7 is a plane view showing the solar cell 1a before the wiring
member 2a is connected, according to a second modification example.

[0023] FIG. 8 is an enlarged section view of the vicinity of the
acceptance face of the solar cell 1a, according to a third modification
example.

DETAILED DESCRIPTION OF THE INVENTION

[0024] Hereinafter, an embodiment of the present invention will be
described with reference to the accompanying drawings. Like parts are
denoted by the same reference numerals and symbols throughout the
drawings.

[0025] An overall configuration of a solar cell module according to an
embodiment of the present invention will be described with reference to
FIG. 1. The solar cell module includes a plurality of (for example,
three) solar cells 1a to 1c. The respective of the solar cells 1a to 1c
is connected in series through a wiring member 2a and a wiring member 2b,
which are formed from copper foil with tinned surfaces. The plurality of
solar cells 1a to 1c is sealed with a translucent sealing member 5 made
of EVA or the like, between a translucent front protective member 3 made
of glass, translucent plastic, or the like and a back protective member
4. The back protective member 4 is made from a PET (or the like) film or
a laminated material obtained by sandwiching a thin metal (such as
aluminum) film between PET (or the like) films, or the like.

[0026] The configuration of the solar cells 1a to 1c and the placement of
the wiring members 2a and 2b in FIG. 1 will be described with reference
to FIGS. 2A and 2B, by taking the solar cells 1a and 1b and the wiring
member 2a as an example. The solar cell 1a includes a photoelectric
conversion body 10a, in which photogenerated carriers are generated by
the incidence of light, and a pair of positive and negative electrodes
for taking the photogenerated carriers generated in the photoelectric
conversion body 10a. The solar cell 1b includes a photoelectric
conversion body 10b, in which photogenerated carriers are generated by
the incidence of light, and a pair of positive and negative electrodes
for taking the photogenerated carriers generated in the photoelectric
conversion body 10b.

[0027] In general, the pair of positive and negative electrodes are
respectively provided on the acceptance face and the back face of each of
the photoelectric conversion bodies 10a and 10b. In this case, the pair
of positive and negative electrodes, those provided on the acceptance
faces is formed into, for example, a comb-like shape by a combination of
a plurality of finger electrodes 21a or 21b having a narrow-width and at
least one bus-bar electrode 11a or 11b having a wide-width, in order to
make an area that blocks incident light as small as possible. The finger
electrodes 21a and 21b are electrodes for collecting the photogenerated
carriers generated in the photoelectric conversion bodies 10a and 10b.
For example, the linear finger electrodes 21a and 21b each having a width
of approximately 100 um are arrayed at intervals of 2 mm across almost
the entire acceptance faces of the photoelectric conversion bodies 10a
and 10b, respectively. Moreover, the bus-bar electrodes 11a and 11b are
electrodes for collecting the photogenerated carriers collected by the
plurality of finger electrodes 21a and 21b. For example, each of the
bus-bar electrodes 11 and 11b is formed into a linear shape with a width
of approximately 1 mm so as to intersect with all the finger electrodes
21a or 21b. The number of each of the bus-bar electrodes 11a and 11b is
appropriately set, with consideration given to the size and resistance of
a solar cell.

[0028] In addition, since the other-polarity electrodes are generally
provided on the back faces of the photoelectric conversion bodies 10a and
10b, incident light does not need to be taken into account. Accordingly,
the other-polarity electrodes may be formed so as to cover almost the
entire back faces of the photoelectric conversion bodies 10a and 10b, or
may be each formed into a comb-like shape similarly to the electrodes on
the acceptance side.

[0029] In the case where the other-polarity electrodes are formed so as to
cover almost the entire back faces of the photoelectric conversion bodies
10a and 10b, a "first main face" of each of the photoelectric conversion
bodies 10a and 10b corresponds to the acceptance face, and a "second main
face" thereof corresponds to the back face. On the other hand, in the
case where the other-polarity electrode is formed into a comb-like shape
on the back face of each of the photoelectric conversion bodies 10a and
10b similarly to the electrodes on the acceptance side, the "first main
face" and "second main face" may be any of the acceptance face and the
back face.

[0030] Additionally, in some solar cells, both of the pair of positive and
negative electrodes are provided on the back face of the photoelectric
conversion body. In this case, each of the pair of positive and negative
electrodes provided on the back face of the photoelectric conversion body
is formed into a comb-like shape having a plurality of finger electrodes
and at least one bus-bar electrode. In this case, a "first main face" of
each of the photoelectric conversion bodies 10a and 10b corresponds to
the back face, and a "second main face" thereof corresponds to the
acceptance face.

[0031] The present invention does not restrict the faces where the pair of
positive and negative electrodes is provided. However, in the present
embodiment, description will be given of the solar cells each having the
pair of positive and negative electrodes on the acceptance face and back
face of the photoelectric conversion body, respectively. Moreover, the
present invention does not restrict the shape of the electrode provided
on the back face of each of the photoelectric conversion bodies 10a and
10b. However, description will be given, as an example, of the solar
cells including the plurality of finger electrodes and bus-bar electrodes
(shown at 12a and 12b in FIG. 2A) also on the back faces of the
photoelectric conversion bodies 10a and 10b.

[0032] The wiring member 2a electrically connects the bus-bar electrode
11a and the bus-bar electrode 12b. The bus-bar electrodes 11a, 11b, 12a,
and 12b are placed on the acceptance faces and the back faces of the
photoelectric conversion bodies 10a and 10b, respectively. The back faces
are the reverse sides of the acceptance faces. The finger electrodes 21a
and 21b are also placed on the acceptance faces and the back faces of the
photoelectric conversion bodies 10a and 10b, respectively.

[0033] The plurality of linear finger electrodes 21a and 21b are arrayed
on the acceptance faces of the photoelectric conversion bodies 10a and
10b, respectively, in parallel with each other at uniform intervals. The
bus-bar electrodes 11a and 11b are placed in the direction orthogonal to
the finger electrodes 21a and 21b, respectively. The finger electrodes
21a and 21b collect photogenerated carriers generated in the
photoelectric conversion bodies 10a and 10b, and the bus-bar electrodes
11a, 11b, 12a, and 12b further collect photogenerated carriers collected
by the plurality of finger electrodes 21a and 21b. The finger electrodes
21a and 21b and the bus-bar electrodes 11a, 11b, 12a, and 12b, which
collect the photogenerated carriers generated by the photoelectric
conversion bodies 10a and 10b, are collectively called "collector
electrodes". The collector electrodes are formed of, for example,
thermosetting conductive resin containing epoxy resin as binder and
conductive particles as filler. Note, however, that these are not
restrictive.

[0034] Incidentally, although not shown in the figures, the finger
electrodes are arrayed not only on the acceptance faces of the
photoelectric conversion bodies 10a and 10b but also on the back faces
thereof similarly. Moreover, the wiring member 2b connected to the solar
cell 1c is connected to the bus-bar electrode 11b. Further, the solar
cell 1c also has a similar configuration to those of the solar cells 1a
and 1b.

[0035] In addition, each of the photoelectric conversion bodies 10a, 10b,
and 10c has a semiconductor junction such as a pn junction or pin
junction and is made from semiconductor material, including crystalline
semiconductor material such as single-crystal silicon or polycrystalline
silicon, thin-film semiconductor material such as amorphous silicon alloy
or copper indium selenide or compound semiconductor material such as
gallium arsenide or indium phosphide, and the like. In recent years,
photoelectric conversion bodies using organic semiconductor material of
dye-sensitized type and the like are also considered.

[0036] Moreover, each of the photoelectric conversion bodies 10a, 10b, and
10c includes a p-type amorphous silicon layer and an n-type amorphous
silicon layer on the top and under surfaces of a single-crystal silicon
wafer, with an i-type amorphous silicon layer interposed between the
amorphous silicon layer and the single-crystal silicon wafer on each
side. An ITO film is formed on the p-type amorphous silicon layers and on
the n-type amorphous silicon layer, respectively. Such a structure, in
which, as described above, a substantially intrinsic amorphous silicon
layer having as large a thickness as it practically does not contribute
to electricity generation is sandwiched between a single-crystal silicon
layer and an impurity-added amorphous silicon layer, is called "HIT
structure" (see Japanese Patent No. 2614561, etc.). The ITO film is
exposed on each of the acceptance face and back face of the photoelectric
conversion body having the HIT structure.

[0037] Referring to FIG. 2B, in this embodiment of the present invention,
the bus-bar electrode 11b has a plurality of opening portions 23. The
plurality of opening portions 23 are arranged at equal intervals in the
direction parallel with the longer side of the bus-bar electrode lib. The
acceptance face of the photoelectric conversion body 10b is exposed on
the bottoms of the opening portions 23. Similarly, each of the other
bus-bar electrodes 11a, 12a, and 12b has similar opening portions 23.

[0038] Description will be given of the photoelectric conversion body 10a,
the bus-bar electrode 11a, and the wiring member 2a, with reference to
FIG. 3. FIG. 3 is an enlarged intersection view of the vicinity of the
acceptance face of the solar cell 1a, taken along the III-III line in
FIG. 2B. A connection layer 13 made of conductive resin is placed between
the bus-bar electrode 11a and the wiring member 2a. The connection layer
13 bonds the bus-bar electrode 11a and the wiring member 2a together and
electrically connects the bus-bar electrode 11a and the wiring member 2a.
The connection layer 13 also fills the opening portions 23 and is in
contact with the acceptance face of the photoelectric conversion body 1a
at the bottoms of the opening portions 23. Accordingly, the connection
layer 13 also bonds the wiring member 2a and the acceptance face of the
photoelectric conversion body 10a through the opening portions 23. Note
that the solar cell module has similar configurations also on the
back-face side of the photoelectric conversion body 10a, on the
acceptance-face side and back-face side of the photoelectric conversion
body 10b, and on the acceptance-face side and back-face side of the
photoelectric conversion body 10c.

[0039] Description will be given of the electrical connection between the
bus-bar electrode 11a and the wiring member 2a in FIG. 3, with reference
to FIG. 4. The connection layer 13 is formed of conductive resin made of
a resin 31 containing a plurality of conductive particles 32. The bus-bar
electrode 11a and the wiring member 2a are electrically connected through
the conductive particles 32. Moreover, the resin 31 bonds the wiring
member 2a and the bus-bar electrode 11a together and also bonds the
wiring member 2a and the acceptance face of the photoelectric conversion
body 10a together.

[0040] As mentioned earlier, the collector electrodes (the finger
electrodes 21a and 21b and the bus-bar electrodes 11a, 11b, 12a, and 12b)
are also formed of conductive resin, similarly to the connection layer
13. Assuming that the material for the connection layer 13 is a "first
conductive resin" and the material for the bus-bar electrodes 11a, 11b,
12a, and 12b is a "second conductive resin", the adhesive strength of the
first conductive resin to the acceptance faces and back faces of the
photoelectric conversion bodies 10a and 10b is stronger than that of the
second conductive resin to the acceptance faces and back faces of the
photoelectric conversion bodies 10a and 10b. Accordingly, by virtue of
the fact that the connection layer 13 bonds the wiring member 2a and the
acceptance face of the photoelectric conversion body 10a together, the
less-strong adhesive strength of the second conductive resin can be
complemented by the connection layer 13 formed of the first conductive
resin.

[0041] Incidentally, the adhesive strength of the first conductive resin
can be enhanced by reducing the density of the conductive particles 32
mixed into the resin 31 (adhesive agent) and thereby increasing the ratio
of the resin 31. Moreover, at the same time, if the conductive particles
32 with high hardness are used, since the conductive particles 32
function as spacers, the distance between the wiring member 2a and the
bus-bar electrode 11a can be kept at a constant value or more. As a
result, since a constant amount or more of the first conductive resin
present between the wiring member 2a and the bus-bar electrode 11a can be
secured, degradation of the adhesive strength occurring along with a
reduction in the amount of the first conductive resin can be suppressed.
Thus, the adhesive strength between the bus-bar electrode 11a and the
wiring member 2a can be satisfactorily maintained.

[0042] However, as the density of the conductive particles 32 is reduced,
the conductivity of the conductive resin is lowered. Therefore, in a
manufacture process step for electrically connecting the wiring members
2a and 2b to the bus-bar electrodes 11a, 11b, 12a, and 12b by applying
pressure in the direction perpendicular to the acceptance faces, the
wiring members 2a and 2b are pressed against the bus-bar electrodes 11a,
11b, 12a, and 12b by applying higher pressure than usual. Thereby, as
shown in FIG. 4, most part of the resin 31 mainly included in the first
conductive resin (the connection layer 13) is squeezed out from between
the wiring member 2a and the bus-bar electrode 11a, with the conductive
particles 32 being left between the wiring member 2a and the bus-bar
electrode 11a, whereby the wiring member 2a and the bus-bar electrode 11a
are electrically connected through the conductive particles 32. Thus,
electrical conduction between the wiring member 2a and the bus-bar
electrode 11a is realized.

[0043] The conductive particles 32 are intended for the provision of
sufficient electrical conductivity between the bus-bar electrode 11a and
the wiring member 2a. For the composition of the conductive particles 32,
at least one kind of metal selecting from a group consisting of nickel,
copper, silver, aluminum, tin, gold, and the like, or an alloy, a
mixture, or the like of any of these metals can be applied. Moreover, at
least one kind of metal-coated inorganic oxide selecting from a group
consisting of alumina, silica, titanium oxide, glass, and the like may be
applied. Alternatively, for the composition of the conductive particles
32, at least one kind of metal-coated resin selecting from a group
consisting of epoxy resin, acrylic resin, polyimide resin, phenolic
resin, urethane resin, silicone resin, and the like, or a metal-coated
copolymer, mixture, or the like of any of these resins may be applied. As
for the shape of the conductive particles 32, a spherical shape with a
circular or an oval intersection taken along a center axis can be
adopted. Moreover, a scheme to enhance the electrical conductivity can
also be adopted, such as increasing the surface areas of the conductive
particles 32 by making their surfaces rugged.

[0044] Preferably, the resin 31 is a material more flexible than the
material used for the wiring member 2a, for the purpose of lessening the
stress occurred expansion and contraction by the temperature changes of
the wiring member 2a. With consideration given to the fact that the resin
31 bonds the wiring member 2a, it is preferable to use a thermosetting
resin material for the resin 31. Moreover, to maintain reliability, the
resin 31 is required to have excellent resistance against humidity and
high-temperature. Examples of a resin meeting these requirements include
epoxy resin, acrylic resin, polyimide resin, phenolic resin, urethane
resin, silicone resin, and the like. At least one kind of resin selecting
from a group consisting of these resins, or a mixture, a copolymer, or
the like of any of these resins can be applied to the resin 31. In terms
of manufacture, epoxy resin or acrylic resin is preferably used, in point
of the capability of setting at low temperature in a short time.
Moreover, any of these resins for the resin 31 may be in the form of a
film that can be deposited by heat.

[0045] Note that, although the collector electrodes (finger and bus-bar
electrodes) are formed of thermosetting conductive resin containing epoxy
resin as binder and conductive particles as filler as described above,
this is an example of the composition of the collector electrodes, and
the present invention is not limited to this composition. For the
composition of the filler in the collector electrodes, which is intended
for the provision of electrical conductivity, at least one kind of metal
selecting from a group consisting of copper, silver, nickel, aluminum,
tin, gold, and the like, or an alloy, a mixture, or the like of any of
these metals can be applied. As for the shape of the filler, a scheme to
enhance the electrical conductivity can be adopted, such as mixing flake
and spherical shapes, or mixing different sizes. Moreover, the binder in
the collector electrodes, whose main purpose is to bond the filler, is
required to have excellent resistance to humidity and high-temperature in
order to maintain reliability. Examples of a material for the binder
meeting such requirements include epoxy resin, acrylic resin, polyimide
resin, phenolic resin, urethane resin, silicone resin, and the like. At
least one kind of resin selecting from a group consisting of these
resins, or a mixture, a copolymer, or the like of any of these resins can
be applied to the binder. As for the proportions of the binder and the
filler, it is preferable that the filler constitute 70% or more of the
conductive resin by weight, with consideration given to electrical
conductivity.

[0046] Additionally, in the case where the solar cell is composed of a
material having high temperature resistance in comparison with amorphous
semiconductors, such as a crystalline semiconductor, then a conductive
resin material that is baked to set at higher temperature than
resin-based conductive resins can be used for the conductive resin. For
example, a bake-type conductive resin composed of powder of metal such as
silver or aluminum, glass frit, organic vehicle, and the like can be
used.

[0047] Referring to FIG. 5, the bus-bar electrode 11a has the plurality of
rectangular opening portions 23. The acceptance face of the photoelectric
conversion body 10a is exposed on the opening portions 23. Each of the
other bus-bar electrodes has a similar shape on a plane view.

First Modification Example

[0048] In the present invention, the planar shape of the bus-bar electrode
is not limited to the one shown in FIG. 5. For example, the bus-bar
electrode may be in a non-rectangular shape such as a round shape. As
shown in FIG. 6, the bus-bar electrode 11a may be in a non-linear shape
and may have a plurality of notch portions 24 instead of the opening
portions 23 in FIG. 5. In FIG. 6, broken lines indicate a region where
the wiring member 2a is arranged. The acceptance face of the
photoelectric conversion body 10a is exposed at the notch portions 24.
The connection layer 13 is in contact with the acceptance face exposed at
the notch portions 24, whereby the wiring member 2a is bonded to both of
the acceptance face of the photoelectric conversion body 10a and the
bus-bar electrode 11a.

Second Modification Example

[0049] The bus-bar electrode 11a may have a plurality of gap portions 25
as shown in FIG. 7 instead of the opening portions 23 in FIG. 5. In FIG.
7, broken lines indicate a region where the wiring member 2a is arranged.
The acceptance face of the photoelectric conversion body 10a is exposed
from the gap portions 25. The gap portions 25 are filled with the
connection layer 13, which is thus in contact with the acceptance face
exposed from the gap portions 25, whereby the wiring member 2a is bonded
to both of the acceptance face of the photoelectric conversion body 10a
and the bus-bar electrode 11a.

Third Modification Example

[0050] In above-mentioned embodiment, the shape of a cross section of the
bus-bar electrode 11a is a rectangular. However, as shown in FIG. 8, an
area A2, which is the area of a first face of the bus-bar electrode 11a
in contact with the acceptance face or back face, may be made larger than
an area A1, which is the area of a second face thereof, the reverse of
the first face. That is, in the bus-bar electrode 11a, the area A2 on the
photoelectric conversion body 10a side may be made larger than the area
A1 on the wiring member 2a side. As described earlier, to electrically
connect between the wiring member 2a and the bus-bar electrode 11a, the
wiring member 2a is pressed against the bus-bar electrode 11a by applying
higher pressure than usual. The pressure applied at this time acts on the
interface between the wiring member 2a and the bus-bar electrode 11a
through the conductive particles 32. Further, the pressure also acts on
the interface between the bus-bar electrode 11a and the photoelectric
conversion body 10a. In this event, the pressure acting on the
photoelectric conversion body 10a is reduced by as much as the area A2 is
larger than the area A1, in inverse proportion to the ratio of the area
A2 to the area A1. That is, the force applied from the bus-bar electrode
11a to the photoelectric conversion body 10a can be reduced depending on
the ratio between the areas of the first and second faces (A2/A1). Thus,
in a manufacture process step for attaching the wiring member 2a to the
solar cell 1a, locally applied pressure can be reduced. Accordingly,
reliability can be enhanced even if the photoelectric conversion body 10a
has insufficient mechanical strength because of the thin wafer or the
like.

(Method for Manufacturing the Solar Cell Module)

[0051] Next, a method for manufacturing the solar cell module according to
the present embodiment will be described.

[0052] First, a method for manufacturing the photoelectric conversion body
10a is similar to conventional methods, and therefore description thereof
will be omitted here. Next, on the photoelectric conversion body 10a, the
bus-bar electrodes 11a and 12a and the finger electrodes 21a are formed
using an epoxy thermosetting silver paste. Specifically, the silver paste
is screen-printed on the acceptance face of the photoelectric conversion
body 10a and then provisionally set by being heated at 150° C. for
five minutes. Thereafter, the silver paste is screen-printed on the back
face of the photoelectric conversion body 10a and then provisionally set
by being heated at 150° C. for five minutes. Thereafter, the
silver paste is completely set by being heated at 200° C. for one
hour, whereby the solar cell 1a is formed. The solar cells 1b and 1c are
also similarly formed.

[0053] Next, using a dispenser, an epoxy resin containing approximately 5%
by volume of nickel particles is applied in a thickness of approximately
30 μm onto the bus-bar electrodes 11a and 12a. After the resin is
applied in this manner onto both of the acceptance face side and the back
face side of the photoelectric conversion body of each of solar cells 1a
to 1c. Next, the wiring members 2a and 2b are placed on the applied resin
and heated at 200° C. for one hour while being pressurized at
approximately 2 MPa, whereby a string is formed.

[0054] Next, each of a plurality of strings is connected. Glass (the front
protective member 3), a sealing sheet (the sealing member 5), the
plurality of strings, a sealing sheet (the sealing member 5), and a back
sheet (the back protective member 4) are stacked in this order and then,
after brought in a vacuum, provisionally compressed together by
thermocompression at 150° C. for ten minutes. Thereafter, this
provisionally compressed body is completely set by being heated at
150° C. for one hour. Thereafter, a terminal box and a metal frame
are attached, thus completing the solar cell module.

OPERATION AND EFFECTS

[0055] As described hereinabove, according to the present embodiment of
the present invention and examples thereof, the following operation and
effects can be obtained.

[0056] The solar cell module includes: the two solar cells 1a and 1b
including the finger electrodes 21a and 21b and the bus-bar electrodes
11a, 11b, 12a, and 12b placed on the acceptance faces and back faces,
which are the reverse sides of the acceptance faces, of the photoelectric
conversion bodies 10a and 10b; the wiring member 2a electrically
connecting the bus-bar electrodes 11a and 12b of the two solar cells 1a
and 1b; and the connection layer 13 formed of the first conductive resin,
placed between the wiring member 2a and the bus-bar electrodes 11a and
12b. The connection layer 13 is also in contact with the acceptance face
or back face of each of the photoelectric conversion bodies 10a and 10b.

[0057] By virtue of the fact that the connection layer 13 is in contact
with the acceptance face or back face of the photoelectric conversion
body 10a, the wiring member 2a is bonded to the acceptance face or back
face of the photoelectric conversion body 10a through the connection
layer 13. Therefore, the connection layer 13 complements the adhesive
strength between the acceptance face or back face of the photoelectric
conversion body 10a and the bus-bar electrode 11a, and accordingly the
reliability of the solar cell module against the temperature changes can
be enhanced.

[0058] It is preferable that the connection layer 13 be in contact with
the acceptance face or back face of the photoelectric conversion body 10a
in a region where the connection layer 13 overlaps with the wiring member
2a when viewed in the direction perpendicular to the acceptance face. The
connection of the connection layer 13 to the photoelectric conversion
body 10a in the region where the connection layer 13 overlaps with the
wiring member 2a further increases the above-mentioned adhesive strength.

[0059] Each of the bus-bar electrodes 11a, 11b, 12a, and 12b has the
opening portions 23, notch portions 24, or gap portions 25. The opening
portions 23, notch portions 24, or gap portions 25 are filled with the
connection layer 13, whereby the connection layer 13 is in contact with
the exposed acceptance face or back face of each of the photoelectric
conversion bodies 10a and 10b. If the connection layer 13 is contact with
the acceptance face or back face of each of the photoelectric conversion
bodies 10a and 10b exposed at the opening portions 23, notch portions 24,
or gap portions 25 formed on the bus-bar electrodes 11a, 11b, 12a, and
12b, the connection layer 13 is inevitably connected to each of the
photoelectric conversion bodies 10a and 10b in the region where the
connection layer 13 overlaps with the wiring member 2a. Accordingly, the
above-mentioned adhesive strength is further increased.

[0060] The bus-bar electrodes 11a, 11b, 12a, and 12b are formed of the
second conductive resin, and the adhesive strength of the first
conductive resin (the connection layer 13) to the acceptance face or back
face is stronger than that of the second conductive resin to the
acceptance face or back face. By virtue of this fact, the connection
layer 13 formed of the first conductive resin can complement the
less-strong adhesive strength of the second conductive resin.

[0061] In each of the bus-bar electrodes 11a, 11b, 12a, and 12b, the area
of the first face, which comes in contact with the acceptance face or
back face, is larger than the area of the second face, which is the
reverse of the first face. By virtue of this fact, in a manufacture
process step for electrically connecting the wiring member 2a to the
bus-bar electrode 11a by applying pressure in the direction perpendicular
to the acceptance face, the pressure applied from the bus-bar electrode
11a to the photoelectric conversion body 10a can be reduced depending on
the ratio between the areas of the first and second faces.

[0062] As described above, the present invention has been described by
using one embodiment and modification examples thereof. However, it
should be understood that the description and accompanying drawings
constituting part of this disclosure are not intended to limit the
present invention. From this disclosure, various alternative embodiments,
examples, and operational techniques will become apparent to those
skilled in the art. That is, it should be understood that the present
invention incorporates various embodiments and the like which are not
described herein. Accordingly, the present invention should be limited
only by matters defining an invention in the claims which are appropriate
from the view point of the description.